1. Field of the Invention
The present invention relates to a modular image sensor array, and more particularly, to such an array in which a plurality of image sensors are assembled in a predetermined pattern on a substrate.
2. Description of the Prior Art
Image scanners are known for reading optical information in the form of text or graphics and converting the optical information into an analog electrical signal. The analog signal is then converted into digital information for image processing and image reproduction. In one arrangement of such a scanner, an image is projected onto a single image sensor by means of demagnification optics. Disadvantages of this arrangement are the necessity for a relatively long light path and the necessity for extreme accuracy in positioning the image sensor. In another type of scanner, as shown, for example in U.S. Pat. No. 4,775,895, an array of image sensors are used in order to overcome the problems associated with the demagnification optics in a scanner using a single sensor.
U.S. Pat. No. 4,775,895, discloses a modular image sensor structure in which a plurality of drive modules are mounted on a substrate of ceramic or glass. Each of the drive modules contains a line of sensor elements. A disadvantage of the structure shown in the patent is that drive modules are spaced from each other on the substrate, and it is very difficult to precisely locate the drive modules relative to each other in order to form a desired pattern of sensor elements. A further disadvantage is that the glass or ceramic substrate is fragile and must be handled with care.